About how much would it cost to make my cars single exhaust into a true dual exhaust?

I have a 1978 Chvy El Camino and i want true dual exhaust on it.





I live in Los Angeles.About how much would it cost to make my cars single exhaust into a true dual exhaust?
if not mistaken in LA u have emission laws correct? then u will need 2 cataylic converters(not cheap), headers, mufflers and the pipes. plus labor on top of that. best thing i would say to do is call muffler places to check it out.but my guess would be around $500, at least that what is is for my 92 camaro,but i do not have to have converters.About how much would it cost to make my cars single exhaust into a true dual exhaust?
$300- in parts, 3 hours labor.
depends on who you call really just look in phone book and call three places